Substrate coil and transformer

Abstract

To provide a board coil capable of obtaining a high inductance value while achieving miniaturization and lowness due to a reduction in loss of the number of turns of the winding pattern.SOLUTION: In a board coil composed of winding patterns provided in a plurality of layers constituting a multilayer substrate, on the winding pattern, a via hole has an elongated shape extending in the radial or circumferential direction of the winding pattern in plan view in the board coil, and from among the winding patterns provided in the plurality of layers, a pair of connection portions of two winding patterns connected to each other, and a pair of connection portions of two winding patterns connected to each other next are formed so as to be aligned in the radial or circumferential direction at a position where the pairs do not overlap in plan view in the board coil.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a substrate coil and a transformer. [Background technology]

[0002] A technique has been proposed for a build-up multilayer board in which a coil pattern is formed on the surface of each layer, and the coil patterns on each layer are connected by build-up vias to form a spiral coil as a whole. This technique does not require the use of coil components, making it possible to miniaturize the coil and obtain a reactance value on the board pattern (see, for example, Patent Document 1).

[0003] Furthermore, as a type of multilayer board, a printed circuit board with a built-in three-dimensional spiral inductor is known, which has a coil in which a coil conductor pattern made of a conductive material is electrically connected by a conductive through-hole, and this printed circuit board with a built-in three-dimensional spiral inductor makes it possible to obtain a high inductance value in a small area (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-077538 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-190934 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-324962 [Patent Document 4] Japanese Patent Publication No. 2020-013827 [Patent Document 5] Japanese Patent Publication No. 2020-013826 [Patent Document 6] Japanese Patent Publication No. 2020-013825 Summary of the Invention [Problem to be solved by the invention]

[0005] In the substrate coils described above, it is generally required that they be made smaller and have a lower height, and that the substrate coils provide appropriate reactance and inductance values.

[0006] However, in the above-described substrate coil, the arrangement of the via holes that connect the winding patterns at the connection portions on the winding patterns is not optimized, and when the area occupied by the via holes on the winding patterns is large, there is a problem in that loss occurs in the winding length of the winding patterns, which makes it difficult to realize a smaller and thinner substrate coil and may increase manufacturing costs.

[0007] The ultimate object of the present invention is to provide a technique that makes it possible to obtain a high inductance value while reducing the size and height of the substrate coil. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides: A substrate coil formed by laminating winding patterns provided on a plurality of layers constituting a multilayer substrate and electrically connecting the winding patterns at connection portions of the winding patterns, the connection portions of the winding pattern have elongated shapes extending in either a radial direction or a circumferential direction of the winding pattern in a plan view, and the connection portions are connected to each other by via holes that are conductive in a direction perpendicular to the plane of the winding pattern, Among the winding patterns provided on the plurality of layers, a pair of connection portions of two overlapping winding patterns connected to each other and a pair of connection portions of two winding patterns connected next to each other are formed so as not to overlap in a plan view on the substrate coil and to be aligned in the other of the radial direction and the circumferential direction. It is a substrate coil.

[0009] According to the present invention, the connection portions of the winding pattern have elongated shapes that extend in either the radial or circumferential direction of the winding pattern in a plan view of the substrate coil, and are arranged perpendicular to the direction in which the connection portions extend, so that the connection portions are arranged densely and efficiently, increasing the area on the winding pattern that can be used as a coil. As a result, it is possible to achieve a smaller and thinner substrate coil.

[0010] Furthermore, in the present invention, the substrate coil may be characterized in that the via holes are arranged in one or two rows in parallel in the direction of extension of the connection parts, which allows the via holes to be arranged in an orderly manner in the connection parts, increasing the density of the via holes and reducing the area of ​​each connection part.

[0011] The present invention may also provide a substrate coil having an input terminal and an output terminal, the connection portion being formed to fit within the space between the input terminal and the output terminal in a plan view, thereby increasing the degree of freedom in arranging the connection portion and suppressing loss in the number of turns of the winding pattern.

[0012] The present invention may also provide a substrate coil including a magnetic core arranged to cover a portion of the winding pattern in a planar view, and the connection portion arranged in a portion where the magnetic core is not provided in a planar view. Here, the magnetic core streamlines the flow of the magnetic field generated by the coil windings and increases the magnetic field. Meanwhile, the magnetic field generated by passing through the via holes has a different direction from the magnetic field generated by the coil windings and can cause disturbance to the magnetic field generated by the coil windings. In contrast, in the present invention, the connection portion is arranged in a portion where the magnetic core is not provided in a planar view, thereby preventing the magnetic field passing through the via holes from disturbing the flow of the magnetic field generated by the magnetic core. As a result, the flow of the magnetic field generated by the substrate coil windings can be more reliably streamlined and increased.

[0013] The present invention may also provide a transformer in which multiple coils are arranged so as to overlap, a current is input to one coil, and an induced current flows through the other coils, and at least some of the multiple coils are substrate coils having the above-described characteristics. This makes it possible to achieve a smaller and thinner transformer while maintaining the stability of the transformer's original functions.

[0014] In the present invention, the means for solving the above problems can be used in combination as much as possible. [Effects of the Invention]

[0015] According to the present invention, it is possible to reduce the loss in the number of turns in the winding pattern, thereby making it possible to reduce the size and height of the substrate coil. Furthermore, by reducing the coil length and increasing the number of turns, it is possible to obtain a high inductance value. By using a substrate coil, it is possible to directly incorporate and embed coils, inductors, transformers, etc. into electronic circuit boards. As a result, it is possible to reduce the size of electronic devices, the number of mounted components, and production costs. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a plan view of a substrate coil according to the first embodiment. [Figure 2] FIG. 10 is a cross-sectional view of a transformer constructed using a substrate coil and a second substrate coil with a different number of turns. [Figure 3] FIG. 10 is a schematic diagram showing the connection state of the winding patterns from the first substrate to the ninth substrate. [Figure 4] FIG. 10 is a plan view for explaining the state of connection when the winding patterns of the first to ninth substrates are connected by a conventional method. [Figure 5]This is a schematic diagram of a substrate coil in which the connection points of the winding patterns of each layer of a multilayer substrate are arranged on the plane of each winding pattern, and via holes are arranged in one or two rows radially of the winding patterns at the connection points. [Figure 6] 1 is a perspective view of a substrate coil combined with a magnetic core in the first embodiment. FIG. [Figure 7] 1 is a plan view showing the winding patterns on each substrate and a combination of a substrate coil and a magnetic core in the first embodiment. FIG. [Figure 8] 10 is a schematic diagram showing a current flow in only one direction when a high frequency current is applied to a substrate coil. FIG. [Figure 9] This is a schematic diagram of a substrate coil in which the connection points of the winding patterns of each layer of a multilayer substrate are arranged on the plane of each winding pattern, and via holes are arranged in one or two rows circumferentially of the winding patterns at the connection points. [Figure 10] 10 is a schematic diagram showing a current flow in only one direction when a high-frequency current is applied to the substrate coil shown in FIG. 9. FIG. [Figure 11] 10 is a plan view showing the winding patterns in each layer and a combination of a substrate coil and a magnetic core in Example 2. FIG. [Figure 12] FIG. 10 is a cross-sectional view of a transformer according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] [Application example] In this application example, a spiral-shaped substrate coil made up of a plurality of winding patterns, each of which has one turn, is applied to a build-up multilayer substrate.

[0018] The roughly circular winding patterns are electrically connected to winding patterns on other layers at their connection points through conductive holes called via holes. Through holes, especially those intended for electrically connecting winding pattern layers, are called via holes. By repeating this configuration, winding patterns are stacked to form a substrate coil. The connection points of the winding patterns have elongated shapes extending radially of the winding patterns in a planar view of the substrate coil. The via holes are arranged in parallel in one or two rows in the direction of the extension of the connection points. A pair of connection points of two overlapping winding patterns connected to each other and a pair of connection points of two next winding patterns are formed in positions on the substrate coil that do not overlap in a planar view. This reduces the area of ​​the connection points created by the via holes and allows the connection points to be densely arranged in specific portions of the winding patterns, thereby alleviating the problem of loss in the number of turns of the winding patterns. As a result, it is possible to achieve the miniaturization and low profile generally required for build-up multilayer substrates.

[0019] In the substrate coil, the top winding pattern and the bottom winding pattern each have an output terminal and an input terminal. The connection part is located in the space between the output terminal and the input terminal in a plan view of the substrate coil. This increases the degree of freedom in arranging the connection part on the winding pattern, making it possible to form a substrate coil with good winding efficiency.

[0020] A substrate coil may include a magnetic core that increases the efficiency of the magnetic field generated by the coil windings. In a planar view of the substrate coil, a portion of the winding pattern is covered by the magnetic core, and the connection portion is located in the portion not covered by the magnetic core. This prevents the magnetic field passing through the via hole at the connection portion from disrupting the magnetic field flow generated by the magnetic core. As a result, it is possible to more reliably increase the efficiency and strength of the magnetic field flow generated by the substrate coil windings.

[0021] Furthermore, the connection portions on the winding patterns may have an elongated shape extending in the circumferential direction of the winding pattern in a planar view of the substrate coil. Compared to a substrate coil having connection portions extending in the radial direction of the winding pattern in a planar view of the substrate coil, the high-frequency current that tends to flow near the inner periphery of the winding pattern due to the skin effect also tends to flow near the outer periphery of the winding pattern. As a result, overheating and reduced reliability due to high-frequency current concentrating through a specific through-hole can be suppressed. Note that the common features are that a pair of connection portions of two overlapping and connected winding patterns and a pair of connection portions of two next connected winding patterns are formed in positions on the substrate coil that do not overlap in a planar view, that the connection portions are contained in the space between the output terminal and the input terminal in a planar view of the substrate coil, and that the connection portions are located in a portion of the substrate coil that is not covered by the magnetic core in a planar view.

[0022] Furthermore, by arranging multiple coils, each including at least one substrate coil having the above characteristics, in a stacked manner, it is possible to form a transformer in which a current is input to one coil and an induced current flows through another coil, and the other coils of the transformer do not have to be substrate coils, each with a different number of turns.

[0023] Example 1 Hereinafter, a substrate coil and a transformer according to a first embodiment of the present invention will be described in detail with reference to the drawings. Note that the substrate coil and the transformer according to the present invention are not intended to be limited to the following configurations.

[0024] <Device configuration> FIG. 1 is a plan view of a substrate coil 10 according to a first embodiment. The substrate coil 10 according to the first embodiment is formed by stacking nine layers of substrates, from a first substrate 1 to a ninth substrate 9, each having a winding pattern, and electrically connecting the winding patterns of two consecutively stacked substrates to form a coil with eight turns. FIG. 1 shows a state in which the topmost first substrate 1 can be seen. Note that the number of layers of the substrate is not limited to nine. Here, substrates 1 to 9 correspond to the multiple layers that make up the multilayer substrate of the present invention.

[0025] The first substrate 1 is provided with a first winding pattern 1a, which is an arc-shaped conductor pattern corresponding to the first layer of the coil. The first substrate 1 is also provided with an output terminal 1b connected to the first winding pattern 1a, and an output terminal 1c connected to a ninth winding pattern 9a on a ninth substrate 9 (not shown) in a manner that penetrates from the second substrate 2 to the eighth substrate 8. The first substrate 1 also has openings 1f, 1g, and 1h for inserting a magnetic core (described below). The winding pattern and the openings for inserting the magnetic core are also provided in common on the second substrate 2 to the ninth substrate 9 (2a-9a, 2f-9f, 2g-9g, 2h-9h).

[0026] 2 is a cross-sectional view of a transformer 30 constructed using a substrate coil 10 and a second substrate coil 20 with a different number of turns. The number of turns of the substrate coil 10 and the second substrate coil 20 may be the same. The transformer 30 is constructed by magnetically connecting the nine-layer (eight turns) substrate coil 10 shown in FIG. 1 and the second substrate coil 20 with a different number of turns using a magnetic core 40. The transformer 30 is constructed by electrically coupling the substrate coils 10 and 20. In this way, by constructing the transformer 30 using the substrate coils 10 and 20, it is possible to achieve a smaller size and a lower height. Similarly, it is also possible to construct an inductor element by combining the substrate coil 10 with a magnetic core 40. Furthermore, both the first coil and the second coil of the transformer 30 do not need to be substrate coils. For example, a normal wire-wound coil may be used instead of the second substrate coil 20.

[0027] The winding pattern provided on each substrate of the substrate coil may be a single turn like the first winding pattern 1a shown in Fig. 1, or may be a multi-turn winding. Using a single winding pattern increases the number of substrates required to increase the number of turns of the substrate coil, but has the advantage of allowing the pattern to be thicker and allowing a larger current to flow.

[0028] 3 is a schematic diagram showing the connection state of winding patterns 1a to 9a on the first substrate 1 to the ninth substrate 9. As shown in the figure, on each substrate, the connection point connecting to the upper substrate and the connection point connecting to the lower substrate are separated, so one turn cannot be formed with one winding pattern, and by stacking the nine substrates from the first substrate 1 to the ninth substrate 9, a substrate coil 10 with eight turns is formed.

[0029] FIG. 4 is a plan view illustrating the connection state when the winding patterns 1a to 9a of each of the first to ninth substrates 1 to 9 are connected using a conventional method. Here, the winding patterns of each substrate are connected to one another through multiple via holes. In reality, in a plan view of the substrate coil 10, only the via hole at the connection point 1d connecting the first winding pattern 1a and the second winding pattern 2a is visible. The via hole at the connection point 8d connecting the eighth winding pattern 8a and the ninth winding pattern 9a is not visible from the connection point 2d connecting the second winding pattern 2a and the third winding pattern 3a. However, in the drawing, to clearly show their relative positions, they are shown as the via hole at the connection point 1d. Here, the connection points correspond to the connection portions in the present invention.

[0030] As is clear from Figure 4, in the conventional winding patterns of each board, the connection points for connecting to the upper board and the connection points for connecting to the lower board are far apart, which reduces winding efficiency. Furthermore, the connection points 1d to 8d are formed so as to be widely distributed on each winding pattern, which also further reduces winding efficiency.

[0031] In contrast, in Example 1, as shown in FIG. 5 , the connection points of the winding patterns on each layer of the multilayer substrate are arranged in an elongated shape extending radially of each winding pattern, and via holes that are conductive perpendicular to the plane of the winding patterns are arranged in one or two rows at the connection points in the radial direction of the winding patterns, which is the direction in which the connection points extend. The figure shows an example in which the connection points are arranged in one row. Furthermore, in the winding patterns of each substrate, the connection points between the winding patterns of the lower substrate and the upper substrate are arranged side by side with a gap between the winding patterns. More specifically, in FIG. 5 , on the second winding pattern 2a of the second substrate 2, a connection point 2d for connection to a connection point 3e of the third winding pattern 3a of the third substrate 3 and a connection point 2e for connection to the first winding pattern 1a (not shown) of the first substrate 1 are arranged side by side with a gap between both ends of the winding patterns.

[0032] FIG. 6 is a perspective view of the substrate coil 10 in Example 1 combined with the magnetic core 40. For simplicity, the figure shows only the coil portion formed by the winding patterns of each substrate. In this way, the magnetic core 40 is arranged such that, in a plan view, the center of the winding pattern is The first winding pattern 1a has a point-symmetric shape and spreads out in a fan shape from the center toward the outer periphery. Only a part of the first winding pattern 1a is covered by the magnetic core 40. .

[0033] The direction of the current flowing from the connection point 1d to the second winding pattern 2a (not shown) is as follows: Since the direction of the current flowing through the first winding pattern 1a is different from that of the current flowing through the first winding pattern 1b, The magnetic force has a different direction. Therefore, when the magnetic field generated around the connection point 1d increases, the magnetic field generated by the current flowing through the first winding pattern 1a is disturbed. Therefore, the connection point 1d is arranged in a portion that is not covered by the magnetic core 40. Note that although FIG. 6 shows the first winding pattern 1a on the first substrate 1 as an example, the same can be said for other winding patterns. The common feature is that only a portion of the feeder pattern is covered by the magnetic core 40 and that the connection points are located in the portions not covered by the magnetic core 40 .

[0034] 7A and 7B are plan views of the winding patterns on each substrate in Example 1, and of the substrate coil 10 combined with the magnetic core 40. FIG. 7A is a plan view of the winding patterns 1a to 9a on the first substrate 1 to the ninth substrate 9. FIG. 7B is a plan view of the winding patterns 1a to 9a stacked in this order and the substrate coil 10 combined with the magnetic core 40. Note that in FIG. 7B, to make the winding patterns 1a to 9a easier to see, only the cross sections of the center core 40a and side cores 40b and 40c of the magnetic core 40 are shown.

[0035] In Example 1, as shown in Fig. 7(a), the winding 10a of the substrate coil 10 is formed by overlapping the winding patterns 1a to 9a on the first to ninth substrates 1 to 9. Each of the winding patterns 1a to 9a is a roughly circular pattern with gaps provided therebetween, and the winding patterns 1a to 9a gradually rotate counterclockwise in order in a plan view of the winding 10a. Furthermore, in a plan view of the winding 10a, the output terminal 1b of the first winding pattern 1a and the input terminal 1i of the ninth winding pattern 9a are adjacent to each other.

[0036] The winding patterns 1a to 9a are gradually rotated counterclockwise, more specifically, the connection points of the winding 10a are gradually rotated counterclockwise in order in a plan view. The connection points are a connection point 1d on the counterclockwise side across a gap in the first winding pattern 1a, and a connection point 2a on the clockwise side across a gap in the second winding pattern 2a. Connection point 2e is connected by a via hole. Similarly, connection point 2d on the counterclockwise side across a gap in second winding pattern 2a is connected by a via hole to connection point 3e on the clockwise side across a gap in third winding pattern 3a. By repeating this structure thereafter, for the bottom via hole of winding 10a, connection point 8d on the left counterclockwise side across a gap in eighth winding pattern 8a is connected by a via hole to connection point 9e on the clockwise side across a gap in ninth winding pattern 9a.

[0037] As shown in FIG. 7(b), connection points 1d (2e), 2d (3e), 3d (4e), 4d (5e), ​​5d (6e), 6d (7e), 7d (8e), and 8d (9e) are closely packed in the space between output terminal 1b and input terminal 1i in a plan view of winding 10a. All of the connection points are located outside the magnetic path defined by magnetic core 40. This reduces the influence of the magnetic field generated by the current flowing through the connection points on winding 10a on the magnetic flow defined by winding 10a and magnetic core 40. Even if winding 10a is rotated relative to magnetic core 40 to some extent, the connection points do not interfere with magnetic core 40 in a plan view, allowing for greater freedom in the placement of the connection points.

[0038] 7(b), as described above, connection points 1d (2e) through 8d (9e) are arranged counterclockwise in this order in a plan view of winding 10a. Furthermore, these eight connection points are arranged so that they do not overlap when viewed in a plan view of winding 10a.

[0039] Example 2 Next, a description will be given of Example 2 of the present invention. In Example 1, an example was described in which via holes for connecting winding patterns formed on two consecutive substrate layers were arranged in the radial direction of the winding patterns at the connection points, but in Example 2, an example will be described in which via holes are arranged in the circumferential direction of the winding patterns at the connection points.

[0040] FIG. 8 is a schematic diagram showing current flow in only one direction when high-frequency current is applied to the substrate coil 100. The thickness of the arrow indicates the magnitude of the current density. Note that the connection points are not shown. As shown in the figure, the skin effect of the high-frequency current causes current density to concentrate in the innermost via holes at the connection points of each winding pattern, resulting in increased heat generation in some via holes and reduced reliability. This can also cause inconveniences such as increased variation in magnetic flux density at each connection point. Note that while FIG. 8 illustrates the current flow in the first winding pattern 11a on the first substrate 11, the same applies to the current flow in the other winding patterns. Furthermore, since the high-frequency current is an AC current, current also flows in the direction opposite to the arrow in FIG. 8, but FIG. 8 shows only the current flowing in one direction.

[0041] In contrast to Example 1, in Example 2, as shown in Fig. 9, the connection points of the winding patterns of each layer of the multilayer substrate are arranged so that they are elongated in the circumferential direction, which is the direction in which the connection points extend, in the plane of each winding pattern, and via holes that are conductive in a direction perpendicular to the plane of the winding patterns are arranged in one or two rows in the circumferential direction of the winding patterns at the connection points. The figure shows an example where the via holes are arranged in one row. The arrangement direction of the via holes at the connection points corresponds to the radial direction shown in Fig. 5 or the other of the circumferential directions shown in Fig. 9. Furthermore, in the winding patterns of each substrate, the connection points with the winding pattern of the lower substrate and the connection points with the winding pattern of the upper substrate are arranged so as to be aligned in the radial direction of the winding patterns. More specifically, in FIG. 9, on the second winding pattern 21a on the second substrate 21, a connection point 21d for connecting to a connection point 31e of the third winding pattern 31a on the third substrate 31 and a connection point 21e for connecting to the first winding pattern 11a (not shown) on the first substrate 11 are arranged in the radial direction of the second winding pattern 21a so as to be aligned in the direction from the outer periphery to the inner periphery of the winding pattern.

[0042] As shown in FIG. 9, by arranging the connection points in the winding pattern so that they are aligned in the radial direction of the winding pattern from the outer periphery to the inner periphery, the radial positions of the via holes at the connection points can be made uniform compared to when the connection points in the winding pattern are aligned in the circumferential direction of the winding pattern, and therefore it is possible to prevent excessive current from concentrating in a specific via hole.

[0043] FIG. 10 is a schematic diagram showing the current flow in only one direction when a high-frequency current is applied to the substrate coil shown in FIG. 9. Note that connection points 21d and 31e are shown in a simplified manner. As shown in FIG. 10, even if the high-frequency current flowing through the winding pattern of each substrate is distributed unevenly toward the inner periphery of the winding pattern due to the skin effect, it flows toward the outer periphery at a connection point located near the outer periphery of the winding pattern, and follows a path that returns from the outer periphery to the inner periphery in the next winding pattern. Therefore, current easily flows toward the outer periphery of the winding pattern of each substrate, and current flows evenly through multiple via holes at the connection points, so This prevents current density from concentrating in a certain via hole. While Fig. 10 illustrates the current flow in the second winding pattern 21a and the third winding pattern 31a, the same applies to the current flow in the other winding patterns. Furthermore, because high-frequency currents are alternating currents, currents also flow in the direction opposite to the arrows in Fig. 10, but Fig. 10 shows only one-way current.

[0044] Fig. 11 is a plan view of the winding patterns on each substrate in Example 2, and of the substrate coil 100 combined with the magnetic core 400. Fig. 11(a) is a plan view of the winding patterns 11a to 91a on the first substrate 11 to the ninth substrate 91. Fig. 11(b) is a plan view of the winding patterns 11a to 91a stacked in this order and the substrate coil 100 combined with the magnetic core 400. Note that in Fig. 11(b), to make the winding patterns 11a to 91a easier to see, only the cross sections of the center core 400a and side cores 400b and 400c of the magnetic core 400 are shown.

[0045] 11(a), the winding 100a of the substrate coil 100 is formed by overlapping the winding patterns 11a-91a of the first substrate 11 to the ninth substrate 91. Each of the winding patterns 11a-91a has a roughly circular pattern with gaps provided between them. In addition, in a plan view of the winding 100a, the output terminal 11b of the first winding pattern 11a and the input terminal 11i of the ninth winding pattern 91a are adjacent to each other.

[0046] Each of the winding patterns 21a to 81a has two connection points in the radial direction of the winding pattern. In the two overlapping and connected winding patterns of the winding 100a, the inner connection point of the upper winding pattern and the outer connection point of the lower winding pattern are connected by via holes. Specifically, connection point 11d, which is the inner connection point of the first winding pattern 11a, is connected by a via hole to connection point 21e, which is the outer connection point of the second winding pattern 21a. Similarly, connection point 21d, which is the inner connection point of the second winding pattern 21a, is connected by a via hole to connection point 31e, which is the outer connection point of the third winding pattern 31a. Thereafter, by repeating this structure, for the bottom via hole of the winding 100a, connection point 81d, which is the inner connection point of the eighth winding pattern 81a, is connected by a via hole to connection point 91e, which is the outer connection point of the ninth winding pattern 91a.

[0047] 11(b), connection points 11d (21e), 21d (31e), 31d (41e), 41d (51e), 51d (61e), 61d (71e), 71d (81e), and 81d (91e) are closely packed into the space between output terminal 11b and input terminal 11i in a plan view of winding 100a. This allows for greater freedom in arranging the connection points on winding 100a while suppressing the effects of magnetic fields generated by currents flowing through the connection points.

[0048] 11(b), as described above, in a plan view of the winding 100a, connection points 11d (21e) through 81d (91e) are arranged in this order radially from the outer periphery to the inner periphery of the winding 100a. Furthermore, these eight connection points are arranged so that they do not overlap when viewed in a plan view of the winding 100a. This makes it easier for current to flow around the periphery throughout the winding 100a.

[0049] Example 3 Next, a third embodiment of the present invention will be described. In the first embodiment, a transformer 30 is provided with substrate coils 10 and 20 in which only a part of the winding pattern is covered by a magnetic core 40. In the third embodiment, a transformer having a substrate coil whose winding pattern is not covered by a magnetic core, and a transformer having a path core structure between two types of coils will be described.

[0050] FIG. 12 is a cross-sectional view of a transformer according to a third embodiment. FIG. 12(a) is a cross-sectional view of a transformer 301 including a substrate coil 101 and a second substrate coil 201 whose winding patterns (not shown) are not covered by a magnetic core 401. The magnetic core 401 is positioned so as to be surrounded by the winding patterns of each substrate. In the configuration of FIG. 12(a), the connection points (not shown) on the winding patterns are not covered by the magnetic core 401. This avoids the drawbacks of disturbances in the magnetic field generated by the current flowing through the winding patterns and unevenness in the amount of magnetic field passing between side cores (not shown), and allows for greater freedom in arranging the connection points.

[0051] FIG. 12(b) is a cross-sectional view of a transformer 302 in which a path core structure is applied between the substrate coil 102 and the second substrate coil 202. To improve the transformer's operating efficiency, an external resonator L is attached. However, arranging the transformer and the resonator L horizontally increases the mounting area, while stacking them vertically requires shielding, resulting in increased height. Therefore, in either case, it is difficult to reduce the size and height of the transformer. In the configuration of FIG. 12(b), by inserting a magnetic core 402 between the substrate coil 102 and the second substrate coil 202 and applying a path core structure, it becomes possible to induce resonance between the substrate coil 102 and the second substrate coil 202 while achieving a reduction in size and height of the transformer 302.

[0052] Also, similar to the transformer 30 of Example 1, the number of turns of the substrate coils 101, 102 and the number of turns of the second substrate coils 201, 202 may be the same or different, and a normal wound coil may be used instead of the second substrate coils 201, 202.

[0053] In the following, the constituent elements of the present invention will be described with reference to the reference numerals in the drawings in order to make it possible to compare the constituent elements of the present invention with the configurations of the embodiments. <Invention 1> A substrate coil (10, 20) formed by laminating winding patterns (1a to 9a) provided on a plurality of layers (1 to 9) constituting a multilayer substrate and electrically connecting the winding patterns at connection portions of the winding patterns, the connection portions of the winding pattern have elongated shapes extending in either a radial direction or a circumferential direction of the winding pattern in a plan view, and the connection portions are connected to each other by via holes that are conductive in a direction perpendicular to the plane of the winding pattern, Among the winding patterns provided on the plurality of layers, a pair of connection portions (1d-9d, 1e-9e) of two overlapping and connected winding patterns and a pair of connection portions (1d-9d, 1e-9e) of two subsequently connected winding patterns are formed so as not to overlap in a plan view on the substrate coil and to be aligned in the other of the radial direction and the circumferential direction. Substrate coil. [Explanation of symbols]

[0054] 1-9: Substrate 1a-9a: Winding pattern 10a: Winding 1b, 1c: Output terminals 1d―9d: Connection points 1e-9e: Connection point 1f―9f: Opening 1g-9g: opening 1h-9h: Opening 1i: Input terminal 10, 20: Substrate coil 30: Trans 40: Magnetic core 40a: Center Core 40b, 40c: Side core

Claims

1. A substrate coil formed by laminating winding patterns provided on a plurality of layers constituting a multilayer substrate and electrically connecting the winding patterns at connection portions of the winding patterns, the connection portions of the winding pattern have elongated shapes extending in a radial direction of the winding pattern in a plan view, and the connection portions are connected to each other by via holes that are conductive in a direction perpendicular to the plane of the winding pattern, Among the winding patterns provided on the plurality of layers, a pair of connection portions of two overlapping winding patterns connected to each other and a pair of connection portions of two winding patterns connected next to each other are formed so as not to overlap in a plan view and to be closely spaced in the circumferential direction, the via holes are arranged in a row across the entire connecting portion in a direction in which the connecting portion extends, It has an input terminal and an output terminal, the input terminal and the output terminal extend in the same direction and are adjacent to each other; the connection portion is formed to fit in the space between the input terminal and the output terminal in a plan view. Substrate coil.

2. a magnetic core disposed so as to cover a portion of the winding pattern in a plan view; The connecting portion is disposed in a portion where the magnetic core is not provided in a plan view. The substrate coil according to claim 1 .

3. A transformer in which multiple coils are arranged so as to overlap, a current is input to one coil, and an induced current flowing through another coil is output, 3. A transformer, wherein at least some of the plurality of coils are the substrate coils according to claim 1 or 2.

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